Background: Although laxatives are a first-line treatment for constipation, there are few randomized placebo-controlled trials assessing their efficacy.
Aim: To determine the effect and safety of oral bisacodyl on stool frequency and consistency in patients with idiopathic constipation.
Methods: 55 patients (age 19-89 years) with idiopathic constipation were recruited from eight primary care practices and randomized to receive bisacodyl, 10 mg once daily, or placebo, on three successive days following a 3-day run-in period. Patients recorded stool frequency and consistency and adverse events. RESULTS; In each treatment group, 27 patients were evaluable for efficacy. The mean number of stools per day was significantly greater in the bisacodyl-treated group (1.8/day) compared with placebo (0.95/day) over the treatment phase (P=0.0061). Mean stool consistency score improved from 'hard' (run-in) to between 'soft' and 'well-formed' during bisacodyl treatment, remaining between 'moderately hard' and 'hard' for placebo treatment (P<0.0001). The investigator's global efficacy score was superior for the bisacodyl group compared with placebo. Both treatments were well tolerated. Serum electrolyte levels and incidence of adverse events were comparable between treatment groups.
Conclusions: Bisacodyl is effective and safe in improving stool frequency and consistency in acute treatment of idiopathic constipation.